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(ModeL) P. H. FOX.

RHBOSTAT FOR ELECTRIC LAMPS.

No. 254,764. Patented Mar. 7,1882.

WITNESSES INVENTOR BY .XAMWW m- ATTORNEYS.

N. PETERS. Pboio-Lllhogmphcr. WnslvinpJom D. C.

UNITED STATES PATENT OFFICE.

PATRICK H. FOX, OF NEW YORK, N. Y.

RHEOSTAT FOR ELECTRIC LAMPS.

SPECIFICATION forming part of Letters Patent No. 254,764, dated March '7, 1882.

Application filed July 7, 1881. (Model) T 0 all whom it man concern:

Beit known that I, PATRICK H. Fox, of the city, county, and State of New York, have invented a new and useful Rheostatfor Electric Lamps, of which the following is a full, clear, and'exact description.

The object of my invention is to provide for regulation of branch currents to the separate lamps.

The invention consists in a spiral coil connect-cd in the circuit and fitted for endwise movement, whereby the wires of the coil are separatcd more or less, and the resistance thus varied. 4

In the accompanying drawings, Figure l is a side elevation of the regulator, and Fig. 2 is a diagram showing the regulator as applied in the circuit of a lamp.

Similar letters of reference indicate corresponding parts.

A is the coil formed of fine wire, preferably German silver. B is the support, consisting of a short rod, of non-conducting material, having alixed collar, a, and a loose collar or slide, 1). The wire is wound loosely in spiral form on the rod, and has its end connected to the two collars a b so that the coil is between them. The loose collar 1) is fitted with a setscrew, 0, or equivalent device, for use in securing the collar in any position in the length of the rod.

By moving the slide 1) out on the rod the coil is stretched and opened, or by a reverse movement the coil is closed, so that there is contact between the numerous turns throughout the whole or any part of its length. The circuit-wires, as shown at d (I, connect to the ends of coil A at the collar a b. The resistance ofl'ered by the coil depends on the length ofthe coiled portion that is opened by adjustment of the slide, as the closed portion of the coil allows the current to pass directly.

In practice I prefer to use fine wire and a coil of numerous turns, so that the required variations can be obtained by a short movement of the collar.

This regulator may be used for the regulation of electric currents generally, and is specially adapted for electric lamps.

Having thus described my invention, I claim as new and desire to secure by Letters Patent-- 1. The regulator for electric circuits,consisting of a loose coil, A, adjustable slide I), and sustaining-rod '13, combined for operation substantially as shown and described.

2. The combination, with the circuit-wires of an electric lamp, of the coil A, fixed at one end, the slide I), and the slide-rod B, substantially as shown and described, for the purposes set forth.

PATRICK H. FOX.

Witnesses:

GEo. D. WALKER, O. SEDGWIOK. 

